Method and apparatus for forming images in anodized sheet metal

ABSTRACT

An apparatus for processing anodized aluminum foil into articles bearing art work or other legends in a completely automated manner. The images in the anodized layer are silver images and are sealed in the pores of the anodized layer. The products are useful as name plates for motors and similar equipment, as markers on ships, etc.

United States Patent Speakman [54] METHOD AND APPARATUS FOR FORMING IMAGES IN ANODIZED SHEET METAL [72] Inventor: John D. Speakman, Hudson, Ohio [73] Assignee: Metalphoto Corporation, a Division of Horizons Research Incorporated 221 Filed: March 17, 1971 211 Appl.No.: 125,189

[52] US. Cl. ..95/89 R, 95/89 A, 95/94 R, 355/100 [51] Int. Cl. ..G03d 3/00 [58] Field of Search ..95/89 R, 89 A, 94 R, 14; 355/100; 96/86, 63; 117/34 [56] References Cited UNlTED STATES PATENTS 3,275,440 9/1966 Kempe ..96/86 X 3,593,641 7/1971 Adams ..95/89 3,552,293 1/1971 Cuthbert ..95/94 R 3,511,160 5/1970 Reusel ..95/14 X 3,465,663 9/1969 Calder ..95/89 A [451 Nov. 14, 1972 2,849,066 8/1958 Michelet et a1. ..226/30 X 3,285,150 11/1966 Wunderle ..95/94 R 3,330,196 7/1967 Chen et al ..95/89 R 3,418,912 12/1968 Land etal ..95/89 R 3,259,048 7/1966 Smith ..95/94 R 3,315,583 4/1967 Hunt ..95/89 R OTHER PUBLICATIONS Aluphoto Plate and Process" 1951 Photographic Engineering, Vol. 2, No. 3, pages 161- 169, author- Eugene Wainer Primary ExaminerJohn M. Horan Assistant Examiner-Alan A. Mathews AttorneyLawrence 1. Field [57] ABSTRACT An apparatus for processing anodized aluminum foil into articles bearing art work or other legends in a completely automated manner. The images in the anodized layer are silver images and are sealed in the pores of the anodized layer. The products are useful as name plates for motors and similar equipment, as markers on ships, etc.

1 Claim, 3 Drawing Figures PATENTEDuav 14 1912 saw 1 or 2 INVENTOR ATTORNEY John D Speokmon METHOD AND APPARATUS FOR FORMING IMAGES IN ANODIZED SHEET METAL This invention relates to a fully automated apparatus in which anodized aluminum foil, e.g., aluminum foil between 0.003 to 0.012 inches in thickness, is processed to finished plates bearing legends or art work of the type described in US. Pat. Nos. 2,1 15,339; 2,126,017; and 2,766,119, the disclosures of which are incorporated herein by reference.

The above noted patents and in other similar prior art publications describe the processing of aluminum sheets, plates and foil for the production of name plates and other art work. In such processes, the aluminum is anodized either chemically or electrochemically. As a result, the surface of the aluminum is provided with a layer of porous aluminum oxide. The pores of the oxide layer are then filled with a photosensitive composition. After photographic exposure and development, the resulting image is sealed in the pores, all of the above steps being accomplished on individual sheets or plates or pieces of foil by means well known in the art.

When efforts are made to carry out the process of U.S. Pat. No. 2,766,l 19 on a continuous basis, i.e., on a continuous strip of anodized aluminum, bearing a freshly developed silver image in its pores, a number of operational difficulties are experienced owing to the presence of a pattern or image in the pores of the anodized aluminum, instead of the uniform surface successfully processed in Mason et al U.S. Pat. Nos. 2,494,954 and 2,538,317 which relate to continuous anodizing, dyeing, and sealing of aluminum strip.

A particularly troublesome condition has been found to exist when processing the anodized foil bearing a freshly formed silver image, before it has been sealed in the pores of the anodized strip. It has been found that the rollers or other means for advancing the strip continuously through the apparatus picks up silver on its surface and thereafter prints" it onto the strip, thereby impairing the quality of the photographically produced image appearing on the strip.

The present invention provides means to insure that such impairment of the image does not occur.

The present invention is directed to other improvements in one or more steps in the above process and in the apparatus for practicing the process, shown schematically in the drawings accompanying this application, in which:

FIG. 1 is a schematic view in the nature of a side view of a production line embodying the invention;

F IG. 2 is a plan view of the apparatus of FIG. 1', and

FIG. 3 is an enlarged view of a portion of the apparatus of FIG. 1.

As shown in HO. 1, anodized aluminum foil strip F which has been impregnated with a photosensitive material is paid out from a reel 6 at an unwind station to a guide roll 8 and thence through the first unit 10 of the foil processing line. Foil strip F may be material which has been anodized in an apparatus such as that described in U.S. Pat. No. 2,494,954, and then impregnated with photosensitive material. In order to permit inspection and testing of the sensitized anodized foil, it is preferred to wind the foil on a reel and feed it into the apparatus as shown. Unit 10 includes the entry guide roller 8 and exit rollers 12 which index the strip F, plus a clamping plate 14 which is operated by an air actuated piston and cylinder 16. Plate 14 may be of sponge rubber or may be of metal provided with a face of sponge rubber or other material which will not mar the surface of the strip F, while it is held stationary at the first unit. A hole punch 18 punches one or more indexing holes in a non-image marginal area of the strip, while the strip is stationary. Other indexing means, such as the marking taught in U.S. Pat. No. 2,849,066 or any other suitable indexing or index-producing means may be used in place of punch 18. While at station 10, the strip is also exposed photographically while it is held stationary against a clear glass or plastic platen 19 by the clamping means 14. A negative or positive may be placed between the clear glass or plastic platen l9 and the foil F. The two are held in perfect contact by plate 14 while being exposed. in platen 19, two areas are provided with clear glass or plastic in the platen so that while one area is in use, the other may be being changed for the next sequence of exposures. Unit 10 also includes a projector lamp. Other means may be provided for projecting an image onto the photosensitive foil.

After the strip has been punched with the indexing holes and has been exposed photographically, it is guided from unit 10 by means of exit rolls 12 which pass it to a looper roll 20. Exit rolls 12 may be programmed so that the desired length of material is advanced to the looper, the length selected corresponding to the length indexed by punch 18. booper roll 20 rides on the strip and maintains tension in the strip, while providing for the intermittent accumulation of strip by the looper during the interval after exposure and while the next section of strip is held stationary while it is being exposed.

From the looper 20, the strip passes into a unit 22 best seen in FlG. 3 in which the strip traverses a train of rolls 100, 101, 102 and 103. Roll is a freely rotatable guide roll which leads the strip from the looper into the developer solution. Each of rolls 101, 102 and 103 is partially immersed in one of a series of liquids as the strip is processed successively with a developer, a photographic stop bath, and a fixing bath.

Rollers 102 and 103 are stainless steel rolls covered with flocking tape 105, three inch diameter type 316 stainless steel covered with a pressure sensitive flocking tape (3MY-9167)having been found very satisfactory. These rollers unlike all of the other rolls in the unit rotate counter to the direction of travel of the foil so that they act to scrub the short stop bath and then the fixing bath into the pores of the anodized layer already containing the developed image.

The liquid level of developer in developer tank 24 and of short stop in tank 26 and of fixer in tank 28 is controlled in each tank by means of stand pipes 25, 27 and 29 in the usual way.

it is at this point in the apparatus that it has been found essential that rollers 102 and 103 act vigorously on the image bearing foil F, to remove any loose silver from the pores of the silver image bearing anodized layer so that the silver will not be picked up later by other rollers further along in the apparatus and printed into the foil.

As the image bearing anodized strip leaves unit 22, it may be inspected by use of a mirror and light 40 arranged at the exit side of unit 22.

The emergent strip now bearing a developed and photographically fixed silver image in the pores of the anodized layer is advanced through a spray rinse 42 in which tap water is sprayed against both the upper and lower surfaces of the strip, and thence to an intensifying tank 44 containing rollers 46 which guide the strip through a liquid bath 48 having a composition suitable for the intensification of the image in the pores of the strip. Such baths are known in the art and need not be described at this time.

The emergent strip passes over a heater 50 which serves to dry the strip, and thence through a rinsing chamber 52 in which sprays of water are directed against both surfaces of the foil F by banks of noules 54. The strip leaves the chamber by passage through rollers 56 which remove excess rinse water from the strip of foil and which direct it into a tank 60. Tank 60 contains a bath 62 of liquid for coloring the foil, for example by application of dye, as is known in the art.

From tank 60 the foil strip passes through a further rinse tank 64, if desired, or it may pass directly into a tank 70 containing a heated solution of nickel acetate or other known sealing material. A train of rolls 72 guide the strip through the tank 70 and are driven at a speed such that residence time of the strip in the tank is a sufficient interval for the image in the strip to be permanently sealed in the pores of the foil before the foil leaves the tank. Tank 70 may contain one or more heaters 74 immersed in sealing bath 70. If preferred, tank 70 may be heated by an external source of heat (not shown) instead.

The strip containing the sealed image is passed to a final rinse tank 80, from which it moves past a heater 82 which may be a radiant heater, or a unit with a blower adapted to remove all traces of liquid from the surface of the strip.

A final series of operations involving the lamination of the foil to an adhesive backing strip 83 paid off of a reel 84, through a laminating roll stand 86 and thence between polishing rolls 88 and drive rolls 90 to a shearing station 92 where the strip is cut to convenient lengths by a shear 94 which is actuated by the holes or marks imparted by punch 18 or similar means which index the strip for shearing means, shear 94 being controlled by a photocell 96, for example.

I claim:

1. A method of processing photosensitized, anodized aluminum foil consisting of an aluminum base having on at least one surface thereof, a porous layer of anodically formed aluminum oxide, and a photosensitive composition in the pores of said oxide, said process comprising:

photographically exposing said photosensitized anodized aluminum;

guiding said foil into a zone in which said foil can accumulate;

thereafter guiding said foil successively into a series of liquids, namely: a developer, a photographic stopbath, and a fixing bath by means of rotatable rolls;

rotating the rollers in said developer bath in the same direction as the travel of said foil, said roller being partially immersed in said developer liquid and passing said foil into said developer liquid and below said rollers; rotating the rollers in each of said photographic stop bath and said fixing bath, counter the direction of travel of said foil, each of said rollers being provided with a roughened surface so that said rollers scrub the processing liquid in which they are partially immersed into the pores of said anodized layer on said foil;

guiding said foil into contact only with the surface of said rolls which is not immersed in said stop bath and fixing bath liquids;

removing any loose silver from the freshly developed silver image in the pores of said anodized foil, by said roughened surfaced rolls;

thenrising said foil and then sealing the fixed silver image in the pores of said foil. 

